Anatomia degli organi e degli apparati - Lymphatic System

Composition:

• Lymphatic vessels

• Lymphatic organs ( primary and secondary)

Function:

1. Absorption of excess of fluid in the interstititun

2. Filtration of lymph

3. Transport of lipid from GI tract to blood circulation

LYMPH: yellowish fluid, same composition as plasma (but not RBC), in lacteal vessels is milky due to fat content

VESSELS:

• Capillaries (blinded end, highly permeable with gap)

• Vessels ( 3 layers structure, and larger one posses valves)

• Ducts ( -Thoracic ducts ( arise from cysterna chyli) ( drains legs,abdomen,left thorax,arm,head and neck) -Right

lymphatic duct (drains right thorax,arm,neck and head))

SECONDARY LYMPHOID ORGANS:

Lymph nodes:

• (capsulated) involve in the filtration of lymph

• hilum efferent and afferent lymphatic vessels

• Parenchyma - cortex (aggregation of lymphocytes

follicles (B) and paracotical region (T)) -medulla

(cords of lymphocytes surrounding the medullary

sinuses + macrophages)

• Filtration ( afferent lymphatic vessels-> subcortical

sinus-> trabecular sinuses-> medullary sinuses-> Lymph node

efferent lymphatic vessels)

• Recirculation of lymphocytes

• MALT: uncapsulated lymphoid tissue aggregates = lymph nodules... Found in the

lamina propria or submucosa layer... Some are macroscopically visible ex. Peyer's

patches in ilium, tonsils, appendix... Peyer's patches